TDA7253L datasheet(5/8 Pages) STMICROELECTRONICS

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TDA7253L

HEAT SINK DIMENSIONING:

In order to avoid the thermal protection intervention, that is placed approximatively at Tj = 150°C, it is important

the dimensioning of the Heat Sinker RTh (°C/W).

The parameters that influence the dimensioning are:

– Maximum dissipated power for the device (Pdmax)

– Max thermal resistance Junction to case (RTh j-c)

– Max. ambient temperature Tamb max

– Quiescent current Iq (mA)

3.1 Example:

VCC = 20V, Rload = 8ohm, RTh j-c = 9 °C/W , Tamb max = 50°C

Pdmax = (N° channels) ·

Pdmax = 1 · ( 2.5 ) + 0.5 = 3W

(Heat Sinker)

In figure 8 is shown the Power derating curve for the device.

Figure 11. Power Derating Curve

lo ad

⋅

--------------------------

⋅

Th c-a

150

am b max

–

d max

-----------------------------------------

Th j-c

–

150

–

----------------------

–

24.3

°C/W

Infinite Heatsink

10 °C/ W

15 °C/ W

20 °C/ W

(d)

(a)

(b)

(c)

040

120

160

Tamb (°C)

Infinite Heatsink

10 °C/ W

15 °C/ W

20 °C/ W

(d)

(a)

(b)

(c)

040

120

160

Tamb (°C)

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